The White-winged Tern, or White-winged Black Tern, Chlidonias leucopterus, is a small tern.

Adult birds in summer have short red legs and a short black bill, a black head, neck and belly, very dark grey back, with a white rump and light grey (almost white) tail. The wings, as the name implies, are mainly white. In non-breeding plumage, most of the black is replaced by white or pale grey.

Their breeding habitat is freshwater marshes across from southeast Europe to central Asia. They usually nest either on floating vegetation in a marsh or on the ground very close to water, laying 2-4 eggs in a nest built of small reed stems and other vegetation. In winter, they migrate to Africa, southern Asia and Australia. It is a scarce vagrant in North America, mainly on the Atlantic coast, but a few records on the Pacific coast and inland in the Great Lakes area.

Like the other "marsh" terns (Chlidonias), and unlike the "white" (Sterna) terns, these birds do not dive for fish, but fly slowly over the water to surface-pick items on the surface and catch insects in flight. They mainly eat insects and small fish.

The name 'White-winged Tern' is the standard in most English-speaking countries; in Britain, this name is also the one used by the formal ornithological recording authorities, but the older alternative 'White-winged Black Tern' is still frequent in popular use.